(r) and
... However, in most systems, two integrals are not sufficient to fully characterize the stellar orbits. In fact, numerical calculations show that most orbits are not completely described by just two integrals, i.e. they admit a third integral. There is no general expression for this integral of motio ...
... However, in most systems, two integrals are not sufficient to fully characterize the stellar orbits. In fact, numerical calculations show that most orbits are not completely described by just two integrals, i.e. they admit a third integral. There is no general expression for this integral of motio ...
Slide 1
... “If it were a star, then the immutable heavens had changed, and the basic contrast between the superlunary region and the corruptible earth was in question. If it were a star, the earth might more easily be conceived as a planet, for the transitory character of terrestrial affairs would now have be ...
... “If it were a star, then the immutable heavens had changed, and the basic contrast between the superlunary region and the corruptible earth was in question. If it were a star, the earth might more easily be conceived as a planet, for the transitory character of terrestrial affairs would now have be ...
Today Only, A New Exhibit: M,L, and T Dwarfs!
... 1999 Kirkpatrick et al. New spectral type is codified, called L and defined to L8, later expanded to L9.5 T is suggested for Gl 229B-like methane dwarfs. Burgasser et al. and Geballe et al. Provided first schemes for T dwarfs (2002) in near-IR, Burgasser et al. 2003 in the visible. Current ...
... 1999 Kirkpatrick et al. New spectral type is codified, called L and defined to L8, later expanded to L9.5 T is suggested for Gl 229B-like methane dwarfs. Burgasser et al. and Geballe et al. Provided first schemes for T dwarfs (2002) in near-IR, Burgasser et al. 2003 in the visible. Current ...
Polaris
... satellite. Concerning the detailed physics, α UMi A is an F7 bright giant (II) or supergiant (Ib). The two smaller companions are: α UMi B an F3V main sequence star, orbiting in 2400 AU distance, and C a very close dwarf on a 18.5 AU orbit. Recent observations show that Polaris may be part of a loos ...
... satellite. Concerning the detailed physics, α UMi A is an F7 bright giant (II) or supergiant (Ib). The two smaller companions are: α UMi B an F3V main sequence star, orbiting in 2400 AU distance, and C a very close dwarf on a 18.5 AU orbit. Recent observations show that Polaris may be part of a loos ...
San Diego Astronomy Association CONTENTS
... ly the carbon core of sun sized stars which have exhausted their hydrogen and helium fuels and released their outer atmospheres as planetary nebula. The carbon cores emerge from the planetary nebula as white-hot remnants unable to support further nuclear fusion and slowly cool over billions of years ...
... ly the carbon core of sun sized stars which have exhausted their hydrogen and helium fuels and released their outer atmospheres as planetary nebula. The carbon cores emerge from the planetary nebula as white-hot remnants unable to support further nuclear fusion and slowly cool over billions of years ...
Chapter 7 Formation of metal-enriched 2nd generation objects 7.1
... little metal is required for gas to cool efficiently – analytical work and simulations suggest that the presence of carbon and oxygen at levels 10−4 − 10−3 Z! would be sufficient for enhanced fragmentation of collapsing gas clouds, signifying a change from the topheavy Population III IMF to a mass f ...
... little metal is required for gas to cool efficiently – analytical work and simulations suggest that the presence of carbon and oxygen at levels 10−4 − 10−3 Z! would be sufficient for enhanced fragmentation of collapsing gas clouds, signifying a change from the topheavy Population III IMF to a mass f ...
Sunstruck
... the core, and the dense helium core compresses the nearby layers. This causes the layers near the core to begin fusing hydrogen into helium again, but at a faster rate than before. The helium being created continues to be deposited into the core and the rate of hydrogen fusion will continue to speed ...
... the core, and the dense helium core compresses the nearby layers. This causes the layers near the core to begin fusing hydrogen into helium again, but at a faster rate than before. The helium being created continues to be deposited into the core and the rate of hydrogen fusion will continue to speed ...
TNO Time Allocation Committee
... Prominences and flares are two of many atmospheric activities exhibited by our Sun. In these events, large amounts of material are released from the Sun’s surface, often thousand of kilometres up from the Sun’s photosphere. Prominences are arcs of gas, held above the surface of the Sun by a strong m ...
... Prominences and flares are two of many atmospheric activities exhibited by our Sun. In these events, large amounts of material are released from the Sun’s surface, often thousand of kilometres up from the Sun’s photosphere. Prominences are arcs of gas, held above the surface of the Sun by a strong m ...
Star 1 A star is a massive, luminous ball of plasma held together by
... spectra of stars such as Sirius to the Sun, they found differences in the strength and number of their absorption lines—the dark lines in a stellar spectra due to the absorption of specific frequencies by the atmosphere. In 1865 Secchi began classifying stars into spectral types.[29] However, the mo ...
... spectra of stars such as Sirius to the Sun, they found differences in the strength and number of their absorption lines—the dark lines in a stellar spectra due to the absorption of specific frequencies by the atmosphere. In 1865 Secchi began classifying stars into spectral types.[29] However, the mo ...
Discovery of White Dwarfs—8 Oct
... Hertzsprung-Russell Diagram of nearby stars 1. Stars in region X are A. Dwarfs B. Giants C. White dwarfs ...
... Hertzsprung-Russell Diagram of nearby stars 1. Stars in region X are A. Dwarfs B. Giants C. White dwarfs ...
AMUSE-Virgo on the survival of super
... AMUSE-Virgo: latest results 26/100 nuclear super-massive Point-like nuclearX-ray X-raysources source likley detected in 32p/100 black objectsholes ...
... AMUSE-Virgo: latest results 26/100 nuclear super-massive Point-like nuclearX-ray X-raysources source likley detected in 32p/100 black objectsholes ...
Formation of Globular Clusters: In and Out of Dwarf
... same microphysics as for young clusters in interacting galaxies model explains observed ages, sizes, masses metallicities correspond to blue/metal-poor clusters ...
... same microphysics as for young clusters in interacting galaxies model explains observed ages, sizes, masses metallicities correspond to blue/metal-poor clusters ...
Ultra faint dwarfs: probing early cosmic star formation
... lower redshifts. Their smaller baryonic content is the result of shock-heating of the infalling gas during major merging events (Cox et al. 2004) which stops accretion. Finally, gas-poor systems formed by merging of recently virialized, Mh > Msf progenitors. Since most of the diffuse gas is still ac ...
... lower redshifts. Their smaller baryonic content is the result of shock-heating of the infalling gas during major merging events (Cox et al. 2004) which stops accretion. Finally, gas-poor systems formed by merging of recently virialized, Mh > Msf progenitors. Since most of the diffuse gas is still ac ...
Producing ultra-strong magnetic fields in neutron star mergers
... In all cases we find that the field in the vortex rolls is amplified within ∼ 1 millisecond by orders of magnitude (Figs. 3 and 4). This time scale should be compared to the 50-100 milliseconds which are estimated (26) for the newly formed, differentially rotating central object to collapse into a b ...
... In all cases we find that the field in the vortex rolls is amplified within ∼ 1 millisecond by orders of magnitude (Figs. 3 and 4). This time scale should be compared to the 50-100 milliseconds which are estimated (26) for the newly formed, differentially rotating central object to collapse into a b ...
Document
... The large fraction of matter in the universe is dark (nonluminous) matter. The need to postulate dark matter was given by Fritz-Zwicky, who observed that galaxies in the coma cluster seemed to be moving to rapidly to be held together by the gravitational attraction of the visible matter. The matter ...
... The large fraction of matter in the universe is dark (nonluminous) matter. The need to postulate dark matter was given by Fritz-Zwicky, who observed that galaxies in the coma cluster seemed to be moving to rapidly to be held together by the gravitational attraction of the visible matter. The matter ...
Distance to the SMC
... Shapley in his calibration must be about 1.5 magnitudes fainter than the spiral arm Cepheids observed by Leavitt. That is, because Shapley based his scale on intrinsically fainter Population II stars, his scale needed to be adjusted to accommodate the intrinsically brighter Population I stars studie ...
... Shapley in his calibration must be about 1.5 magnitudes fainter than the spiral arm Cepheids observed by Leavitt. That is, because Shapley based his scale on intrinsically fainter Population II stars, his scale needed to be adjusted to accommodate the intrinsically brighter Population I stars studie ...
NuSeti-2015 - Department of Physics and Astronomy
... •A Cepheid variable is a member of a particular class of variable stars, notable for tight correlation between their period of variability and absolute luminosity. • Namesake and prototype of these variables is the star Delta Cephei, discovered to be variable by John Goodricke in 1784. • This corre ...
... •A Cepheid variable is a member of a particular class of variable stars, notable for tight correlation between their period of variability and absolute luminosity. • Namesake and prototype of these variables is the star Delta Cephei, discovered to be variable by John Goodricke in 1784. • This corre ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.